[0001] The present invention relates to a stimuli-responsive composition which contains
a polymer, a solvent and a substance having a predetermined function, and which is
usable for various functional materials. More particularly, the present invention
relates to a composition which is an aqueous dispersion, and also relates to an image-forming
material which is favorably usable for printers and displays, and a device, an image-forming
method and an image-forming apparatus using it.
[0002] The present invention also relates to an ABC type triblock polymer compound which
is an ABC type block polymer compound, and which comprises, as respective blocks,
an A block which is solvent-phobic (hereinafter called solvophobic), a B block which
changes in nature from solvent-philic (hereinafter called solvophilic) to solvophobic
or from solvophobic to solvophilic in response to stimuli, and a C block which is
solvophilic. More preferably, the invention relates to an ABC type triblock polymer
compound in which each of the blocks changes in nature from solvophobic to solvophilic
or from solvophilic to solvophobic in response to stimuli, and this change occurs
sequentially, first in the A block, then in the B block, and finally in the C block.
[0003] Among dispersion materials containing particulate solids, coloring materials, such
as ink and toner, which contain colorants as particulate solids, have been widely
known as functional materials. In recent years, digital printing techniques have advanced
with marked momentum. Typical examples of the digital printing techniques are electrophotography
and ink-jet technology. Their presence has drawn increased attention as image-forming
techniques in the office and at home.
[0004] Of them, the ink- jet technology has great features, compactness and reduced power
consumption, as a direct method of image-forming . In this technology, a high image
quality has been achieved promptly because of a fine nozzle and so on. An example
of the ink-jet technology is a so-called bubble jet (a registered trademark) method
by which ink supplied from an ink tank is heated with a heater in the nozzle to cause
film boiling, and the ink is ejected by the force of the film boiling to form an image
on a recording medium. Another example is a method which involves vibrating a piezo
element to eject ink from the nozzle. In these methods, further improvements are desired
to counter bleeding or feathering. To realize these improvements, the use of pigment
dispersion ink is under study (for example, United States Patent 5,085,698), but a
further improvement is desired.
[0005] The object of the present invention is to provide a stimuli-responsive composition
containing a block polymer, a solvent and a coloring material, and a pigment dispersion
ink material containing this composition. Particularly, the object of the invention
is to provide a pigment dispersion ink composition comprising the composition in which
the solvent is water and the coloring material is a pigment, the pigment dispersion
ink composition being high in dispersion stability, improved over conventional ones
in terms of bleeding and feathering, and having excellent fixing properties, and a
pigment dispersion ink material containing the pigment dispersion ink composition.
[0006] These objects are achieved by the ABC type block polymer according to claims 1 or
2, the composition comprising a block polymer according to claims 3 or 19, the ink
composition according to claim 10, the image forming method according to claim 11,
the image forming apparatus according to claim 15, the recording medium according
to claim 17 and the information display device according to claim 18. The other claims
relate to further developments.
[0007] EP-A-1243624, published on 29/09/02 and claiming priorities of 23/03/01, 10/07/01
and 18/03/02, discloses a block polymer having the following structure:

with i-Pr designating i-propyl, Et designating ethyl and x, y, z designating the number
of repeating units, respectively.
[0008] The above and other objects, effects, features and advantages of the present invention
will become more apparent from the following description of embodiments thereof taken
in conjunction with the accompanying drawings.
[0009] FIG. 1 is a block diagram showing the constitution of an ink-jet recorder.
[0010] The present invention will now be described in detail.
[0011] The first aspect of the present invention is a composition which contains a block
polymer, a solvent, and a coloring material, and which forms a micelle, the composition
undergoing a change from a first micelle state to a second micelle state different
therefrom in response to stimuli.
[0012] The micelle referred to here includes a micelle which an amphipathic substance forms
in an aqueous solvent, and a so-called reversed micelle which an amphipathic substance
forms in an organic solvent. In the present invention, the use of water as a main
solvent is preferred. These micelles are formed in a form containing the block polymer.
Thus, the block polymer preferably has an amphipathic property. The present invention
is characterized in that the composition changes from a certain micelle (the first
micelle state) to a micelle different therefrom (the second micelle state) in response
to stimuli. This change is, for example, such a change that the properties of the
micelle, such as micelle radius, zeta potential, and molecular motility, change, thereby
causing the micelle to change into a different micelle state. These changes in the
properties can be easily detected by means such as laser diffraction or light scattering,
electrophoresis, and nuclear magnetic resonance spectrum, respectively.
[0013] In the present invention, the facts that such a change in the micelle state occurs
in response to stimuli, and is accompanied, for example, by a critical change in the
viscosity are preferred, because these facts enable the composition of the present
invention to be used as an ink material with excellent fixing properties. For similar
reasons, the above change being accompanied by a change in the composition from sol
to gel is further preferred.
[0014] The expression "critical change" as used herein refers to the fact that the composition
of the present invention changes in the state of the micelle, formed by the polymer
contained in the composition, from a certain state to a different micelle state in
response to stimuli, thereby causing a marked change in the state of the composition
as compared with the state existent before application of the stimulating conditions;
or that the properties of the composition are, in dependence on stimuli conditions,
changed to a different state in tendency at the borderline between before and after
giving certain stimuli conditions. For example, what is designated as "the critical
change of viscosity" means that the state of the micelle formed by the polymer in
the composition of the present invention changes from a certain state to a different
micelle state in response to predetermined stimuli, thereby causing a great change
in the viscosity of the composition as compared with the state existent before application
of the stimuli, for example, the change of the composition from a liquid state to
a semisolid state. The aforementioned sol-to-gel change, for example, can be included
in such a critical change in the viscosity. The critical change may be a sudden change
or a gradual slow change.
[0015] The cause of the above change in the micelle state is preferably a change in the
properties of at least one of the blocks of the block polymer by stimuli. Concretely,
the change of the properties of the relevant block includes, for example, the change
of the block from hydrophobic property to hydrophilic property, the change of the
block from hydrophilic property to hydrophobic property, or the change of the degree
of hydrophilicity.
[0016] The block polymer essentially used in the composition of the present invention is
preferably amphipathic. This block polymer plays a central role in micelle formation,
and can take at least two different micelle states. This is a major characteristic
of the present invention. In the ABC type triblock polymer compound the change from
solvophobic property to solvophilic property or from solvophilic property to solvophobic
property in response to stimuli occurs sequentially, first in the A block, then in
the B block, and finally in the C block.
[0017] In the present invention, a polymer containing a polyvinyl ether structure is used
as the structure of the block polymer. Such a polymer can be synthesized as a block
polymer by the cation living polymerization method. The concrete repeating unit structure
of the polymer is preferably the structure shown by the following general formula
(1):
General formula (1)
-(CH
2-CH(OR
1))- (1)
where R
1 is selected from linear, branched or cyclic alkyl groups having 1 to 18 carbon atoms,
phenyl (Ph), pyridyl (Pyr), Ph-Ph, Ph-Pyr, or -(CH(R
2)-CH(R
3)-O)
1-R
4 or - (CH
2)
m-(O)
n-R
4; the hydrogen on the aromatic ring can be substituted by a linear or branched alkyl
group having 1 to 4 carbon atoms, and the carbon in the aromatic ring can be substituted
by nitrogen; 1 is selected from integers of 1 to 18, m is selected from integers of
1 to 36, n is 0 or 1; R
2 and R
3 are each independently H or CH
3; R
4 comprises H, a linear, branched or cyclic alkyl group having 1 to 18 carbon atoms,
Ph, Pyr, Ph-Ph, Ph-Pyr, -CHO, -CH
2CHO, -CO-CH=CH
2, -CO-C(CH
3)=CH
2, or CH
2COOR
5, provided that when R
4 is other than hydrogen, the hydrogen on the carbon atom can be substituted by a linear
or branched alkyl group having 1 to 4 carbon atoms, F, Cl or Br, and the carbon in
the aromatic ring can be substituted by nitrogen; and R
5 is H or an alkyl group having 1 to 5 carbon atoms. This polymer will be described
in detail later on.
[0018] The composition of the present invention, as stated earlier, is characterized by
changing from a state in which it takes a certain micelle form to a state in which
it takes a different micelle form, in response to stimuli. According to the invention,
This responsiveness is to a temperature change. It may also be to exposure to electromagnetic
waves, may be to a pH change, or may be to a change in the concentration of the composition,
and at least two of these stimuli may be combined.
[0019] The composition of the present invention, as discussed already, is effectively used
as an image-forming material, and effectively used as an ink composition, in particular.
The composition can also be used preferably as ink-jet ink for an ink-jet process.
[0020] The composition of the present invention is a functional material, and contains a
block polymer, a solvent, and a coloring material. Thus, in addition to the above-described
use for the ink composition, the composition of the invention can be used, typically,
as a composition usable for cosmetics, such as lipsticks, foundations, rouge, and
moisturizing creams, or as a coloring material such as a toner containing a colorant.
[0021] Since the composition of the present invention is preferably used as an image-forming
material, as will be described later on, the coloring material contained in the composition
is preferably a pigment or a dye.
[0022] The composition of the present invention also contains a solvent. The solvent contained
in this composition refers to, but is not limited to, a medium capable of dissolving,
suspending or dispersing the components contained in the composition. In the present
invention, organic solvents such as various aliphatic hydrocarbons with a linear,
branched or cyclic structure, aromatic hydrocarbons and heteroaromatic hydrocarbons;
aqueous solvents; and water are contained as solvents. Water and an aqueous solvent,
in particular, can be used preferably in the composition of the present invention.
Examples of the aqueous solvent are polyhydric alcohols such as ethylene glycol, diethylene
glycol, triethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol,
and glycerin; polyhydric alcohol ethers such as ethylene glycol monomethyl ether,
ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol
monoethyl ether, and diethylene glycol monobutyl ether; and nitrogen-containing solvents
such as N-methyl-2-pyrrolidone, substituted pyrrolidone, and triethanolamine. For
uses as ink, monohydric alcohols, such as methanol, ethanol and isopropyl alcohol,
can be used to quicken drying on paper.
[0023] The composition of the present invention is characterized by responding to stimuli
and changing in properties. When used in cosmetics, the composition can impart, for
example, the function of increasing retention on the skin, or the function of making
color fadeout difficult, because of its properties changing from the point of makeup
onward.
[0024] Particularly preferred in the present invention is the utilization of the composition
as a coloring material whose properties change responsive to stimuli. When the composition
of the present invention is used as a pigment dispersion ink material, this composition
gives high dispersion stability to the pigment, is improved in bleeding or feathering
when adhered to a recording medium, and is highly fixable. Thus, the composition of
the present invention as the pigment dispersion ink material can be utilized as a
high image quality, low energy consumption, high speed image-forming material.
[0025] The block polymer characteristically used in the present invention plays a central
role in satisfactorily dispersing a substance, which has a predetermined function,
in a solvent, and changing in the micelle state in response to stimuli. The block
polymer can substantially retain the properties of repeating unit structures of the
respective blocks or units, and show these properties in a coexistent form. The block
polymer used in the composition of the present invention has the amphipathic units,
and forms a micelle and disperses in water highly. The block or unit portions having
responsiveness to stimuli function effectively, and their functionality can appear
efficiently compared with a random polymer. In a preferred embodiment of the present
invention, a block polymer containing the polyvinyl ether structure to be described
below is preferably used. In the present invention, moreover, it is also possible
to use a graft polymer or a graduation polymer in which the polymer contains a polyvinyl
ether structure.
[0026] An example used to explain the present invention is an ABC type triblock polymer
in which two of the respective blocks have two or more different kinds of hydrophilic
blocks, and the remaining one block is hydrophobic. When such an amphipathic triblock
polymer is dispersed in water, a micelle is formed. The term "different" herein refers
to a different chemical structure. That is, it means that the monomer structure of
the each block is different, or that copolymerization ratio of the branched structure
in the polymer chain is different, and it does not mean that only the molecular chain
length of the single repeating unit in the polymer chain is different. Thus, each
block may comprise a single repeating unit structure, or may comprise a plurality
of randomly repeating unit structures, or may take a form in which the proportions
of plural repeating unit structures gradually change. Of the two kinds of hydrophilic
blocks of the triblock polymer, one of the blocks is a block which changes in nature
from hydrophilic to hydrophobic in response to stimuli. This block can inversely change
from hydrophobic to hydrophilic depending on conditions after becoming hydrophobic.
The block polymer having such a block is such that at least one of the hydrophilic
blocks among the two or more different kinds of hydrophilic blocks responds to stimuli
and changes from hydrophilic to hydrophobic. Owing to this phenomenon, the block polymer
changes into the state of a micelle different from the micelle present before response
to the stimuli, thereby changing the properties of the composition, for instance,
viscosity. Conversely, the block, which showed a hydrophobic property under certain
conditions, can change into a hydrophilic block in response to stimuli, thereby changing
the properties of the composition, for instance, viscosity. When the state of the
micelle changes in this manner, the measurement of the micelle radius by laser diffraction
or light scattering shows that this radius after response to stimuli has changed greatly
compared with that before response to stimuli.
[0027] As noted above, the change in the micelle state affects, directly or indirectly,
the various properties of the composition, including viscosity. For example, if the
response to stimuli is that to a temperature change, the micelle radius changes critically
in response to the temperature change (that is, the radius changes rapidly or gradually,
with the temperature conditions or temperature change serving as the borderline conditions).
Responsive to this change in the micelle radius, viscosity, for example, critically
changes according to the temperature change. Depending on the structure of the block
polymer or the type of stimuli given, an even greater viscosity change occurs, and
can result in the transition of the composition in the sol state into gel.
[0028] The above-described form of the block polymer is a basic skeleton of the polymer
structure, and the block polymer of the present invention can include variously modified
structures, for example, those having a straight chain terminal or a branch terminal
modified with a functional group, those having a straight chain terminal portion or
a branch terminal portion chemically or physically adsorbed to a functional substance,
or those grafted to other polymer.
[0029] The polyvinyl ethers will be described below, which are preferably used as the block
polymer of the present invention. The polymer having polyvinyl ether structure has
more preferable dispersibility, since the polyvinyl ether structure generally has
a low glass transition point and has flexible property, thereby having compatible
points where the hydrophobic segments are physically entangled with pigments and are
easy to be compatible with them. Many reports have been made, regarding synthesis
of block polymer having polyvinyl ether structures (for example, JP-A 080221/1999).
Among them, the typical method is cation living polymerization described by Aoshima
et al. (JP-A 322942/1999, JP-A 322866/1999). The synthetic method of the polymer using
cation living polymerization gives various polymers such as block polymers, graft
polymers and graduation polymers, with a uniform length (molecular weight) accurately.
Polyvinyl ethers may have various functional groups introduced into the side chains
thereof. Cation polymerization method may also be effected in HI/I
2 or HCl/SnCl
4 system or the like.
[0030] Though not specifically being limited, the molecular structure of the repeating units
of the polymer having polyvinyl ether structure is preferably represented by the following
general formula (1):
-(CH
2-CH(OR
1))- (1)
wherein R
1 is selected from a linear, branched or cyclic alkyl group having from 1 to 18 carbon
atoms, a phenyl (Ph) group, a pyridyl (Pyr) group, or a group of Ph-Ph, Ph-Pyr, -(CH(R
2)-CH(R
3)-O)
1-R
4 and -(CH
2)
m-(O)
n-R
4; the hydrogen atom on the aromatic ring may be substituted with a linear or branched
alkyl group having from 1 to 4 carbon atoms; and the carbon in the aromatic ring may
be substituted with a nitrogen atom; 1 is an integer 1 to 18; m is an integer 1 to
36; and n is 0 or 1; R
2 and R
3 each independently represent H or CH
3, preferably both R
2 and R
3 are H (that is, -(CH
2-CH
2-O)
1-R
4); R
4 comprises H, a linear, branched or cyclic alkyl group having 1 to 18 carbon atoms,
Ph, Pyr, Ph-Ph, Ph-Pyr, -CHO, -CH
2CHO, -CO-CH=CH
2, -CO-C(CH
3)=CH
2, or CH
2COOR
5, provided that when R
4 is other than hydrogen, the hydrogen on the carbon atom can be substituted by a linear
or branched alkyl group having 1 to 4 carbon atoms, F, Cl or Br, and the carbon in
the aromatic ring can be substituted by nitrogen; and R
5 is H or an alkyl group having 1 to 5 carbon atoms.
[0031] In the present invention, the linear or branched alkyl group includes, for example,
methyl, ethyl, n-propyl, i-propyl, n-butyl, sec-butyl, tert-butyl, pentyl, n-hexyl,
heptyl, octyl, nonyl, decyl, undecyl, dodecyl and octadecyl groups. The cyclic alkyl
group includes, for example, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and
cyclooctyl groups. When hydrogen atom on the carbon atom is substituted, substitution
may occur at one or more positions.
[0033] The structures of the vinyl ether polymers formed from these vinyl ether monomers
will be cited below, but the polymers for use in the present invention are not limited
thereto. If the polyvinyl ether structure is formed from two or more vinyl ether monomer
components, namely, if the vinyl ether polymer is a copolymer, the vinyl ether polymer
may be a random polymer, a block polymer, a graduation polymer, or a graft polymer.
Examples of the copolymer used in the present invention are listed below, but the
copolymers of the present invention are not limited thereto.
(II-g) -[CH
2-CH(OCH
2CH
2-OCH
3)]
x-b-{[CH
2-CH(OCH
2CH
2-OC
2H
5)]
p-r-[CH
2-CH(OCH
2CH
2-OCH
3)]
q}
y-b-[CH
2-CH(OCH
2CH
2-OC
2H
5)]
z-
(II-h) -[CH
2-CH(OCH
2CH
2-CH(CH
3)
2)]
x-b-[CH
2-CH(OCH
2CH
2-OC
2H
5)]
y-
(II-i) -[CH
2-CH(OCH
2CH
2-OCH
3)]
x-b-[CH
2-CH(OCH
2CH
2-OCH
2CH
2-OC
2H
5)]yb-[CH
2-CH(OCH
2CH
2-OC
2H
5)]
x-
(II-j) -[CH
2-CH(OCH
2CH
2-OH)]
x-b-[CH
2-CH(OCH
2CH
2-OC
2H
5)]
y-
(II-k) -[CH
2-CH(OCH
2CH
2CH
2CH
2-OH)]
x-b-[CH
2-CH(OCH
2CH
2-OC
2H
5)]
y'-
(II-l) -[CH
2-CH(OCH
2CH
2-OC
2H
5)]
x-b-[CH
2-CH(OCH
2CH
2-OCOC(CH
3)=CH
2)]
y-
[0034] Further preferably, the numbers (x, y, z) of the repeating units of the polyvinyl
ether are each independently 1 or more, but 10,000 or less; p and q are each 0 or
more, but 1 or less, and the sum of P and q is 1. More preferably, the total number
(x + y + z) of the repeating units is 10 or more, but 40,000 or less.
[0035] Further concrete examples of the polyvinyl ether polymers shown above will be described.
In an aqueous solvent, the properties of the block from the monomer component I-b
are such that when heated, the block changes from hydrophilic property to hydrophobic
property at about 70°C, as disclosed in Polymer Preprints, Japan Vol. 49, No. 12,
3653(2000). The properties of the block from the monomer component I-c are similarly
such that when heated, the block changes from hydrophilic property to hydrophobic
property at about 20°C, as disclosed in Polymer Preprints, Japan Vol. 49, No. 12,
3653(2000). In connection with the block of a random polymer from I-b and I-c, a change
of property occurs at a temperature between the transition temperatures of the respective
monomer components according to their proportions, as shown in Polymer Preprints,
Japan Vol. 49, No. 12, 1226(2000). Utilizing these phenomena, if an ABC block polymer
composed of a block A comprising the monomer component I-b, a block B comprising a
random copolymer of I-b and I-c (ratio in copolymer: 1:1), and a block C comprising
the monomer component I-c is used, in the range from about 20°C until about 40°C that
the modification temperature of the random copolymer B, a micelle state in which the
C block is the hydrophobic center can be developed, and in the range from about 40°C
that the property-changing temperature of the random copolymer, until about 70°C that
the property-changing temperature of the block A comprising the monomer component
I-b, a micelle state in which the B block and the C block having a hydrophobic property
can be developed. The former micelle and the latter micelle are clearly different,
and can be easily detected by dynamic light scattering, laser diffraction, or nuclear
magnetic resonance spectrum. In the present invention, the pigment is preferably coexistent
in a form having an affinity for the hydrophobic block.
[0036] In the composition of the present invention, the particle size, average particle
size (radius), of the micelle is preferably 5 nm or more, but 100 nm or less. If the
average particle size (radius) of the micelle is 5 nm or more, but 100 nm or less,
dispersion of the pigment takes place satisfactorily.
[0037] The composition of the present invention changes in its micelle state in response
to various stimuli. Examples of the stimuli in the present invention are a temperature
change, application of an electric field, exposure to light (electromagnetic waves)
such as ultraviolet rays, visible rays or infrared rays, a change in the pH of the
composition, addition of a chemical substance, and a change in the concentration of
the composition. Herein, "stimuli-responsive (or stimuli-responsiveness)" means that
the composition of the present invention changes in properties in response to the
stimuli as described above. That is, "stimuli-responsive (or stimuli-responsiveness)"
refers to the fact that when stimuli, such as exposure to electromagnetic waves, application
of an electric field, temperature change, pH change, addition of a chemical substance,
or a change in the concentration of the composition, are applied to the composition,
the properties of the composition change in accordance with the stimuli (environmental
change). The change in the properties can be selected variously according to the purpose
of use of the composition of the present invention. For utilization as an image-forming
material, for example, the composition undergoes a sudden increase in viscosity or
a sudden phase change (e.g., change from sol to gel) in response to stimuli, resulting
in an increase in fixing onto a recording medium. In the present invention, preferred
examples of stimuli-responsiveness are as follows: a first one is that to a temperature
change, the range of the temperature change being the range across the phase transition
temperature of the composition. In the composition of the present invention, moreover,
stimuli-responsiveness is that to exposure to electromagnetic waves, whose wavelengths
preferably range from 100 to 800 nm. In the composition of the present invention,
moreover, stimuli-responsiveness is that to the pH change of the composition, the
range of the pH change being preferably from pH 3 to pH 12. The stimuli-responsiveness
in the present invention further includes that to a change in the concentration of
the composition. Examples of the stimuli in this case include a concentration change
due to evaporation or absorption of the solvent of the composition, and a change in
the concentration of the composition as a result of a change in the concentration
of the dissolved polymer in the composition. With such stimuli, the change in the
concentration is preferably in the range covering concentrations across the concentration
at which the composition undergoes phase transition. In the present invention, at
least two of these stimuli may be combined.
[0038] The composition of the present invention has various applications, such as agricultural
chemicals, medicines, cosmetics, and coloring materials. Particularly preferred use
is in an ink material containing a pigment or a dye, and using water or other solvent.
The use of the composition of the present invention makes it possible to improve various
properties of the ink material, including fixing properties. The composition is also
used preferably as ink for an ink-jet printer.
[0039] Next, the components of the composition of the present invention, other than the
block polymer, will be described in detail. [Water]
[0040] Water in the aqueous dispersion of the present invention is preferably ion-exchange
water not containing metal ions, pure water, or ultra-pure water.
[Aqueous Solvent]
[0041] For the aqueous solvent, for example, usable are polyalcohols such as ethylene glycol,
diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, polypropylene
glycol, glycerin; polyalcohol ethers such as ethylene glycol monomethyl ether, ethylene
glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl
ether, diethylene glycol monobutyl ether; and nitrogen-containing solvents such as
N-methyl-2-pyrrolidone, substituted pyrrolidones, triethanolamine. For accelerating
the drying speed of the aqueous dispersion on recording media, usable are monohydric
alcohols such as methanol, ethanol, isopropyl alcohol.
[0042] In case where the composition of the present invention is ink, the content of the
water or aqueous solvent is preferably a range of 20 to 95 % by weight, more preferably
30 to 90 % by weight based on the total weight of the aqueous dispersion.
[Coloring Material]
[0043] The useful coloring material in the present invention can use a pigment, a dye, etc.
according to the uses of the composition of the present invention. The amount of the
coloring material used in the present invention is preferably 0.1 to 50% by weight
based on the weight of the composition of the present invention.
[0044] In the case of ink, a preferred embodiment of the present invention, a dye or a pigment
is usually used. Concrete examples of the pigment and the dye for the application
of the aqueous dispersion of the present invention as ink will be described below.
The pigment may be an organic pigment or an inorganic pigment, and the pigment used
in ink includes, preferably, a black pigment and pigments of the three primary colors,
cyan, magenta and yellow. Furthermore, color pigments other than those stated above,
colorless or light-color pigments, and pigments with a metallic luster may be used.
Besides, newly synthesized pigments may be used for the present invention.
[0045] Examples of commercially-available black, cyan, magenta and yellow pigments are mentioned
below.
[0046] Black pigments are, not limited to, Raven 1060, Raven 1080, Raven 1170, Raven 1200,
Raven 1250, Raven 1255, Raven 1500, Raven 2000, Raven 3500, Raven 5250, Raven 5750,
Raven 7000, Raven 5000 ULTRAII, Raven 1190 ULTRAII (all by Columbia Carbon); Black
Pearls L, MOGUL-L, Regal 400R, Regal 660R, Regal 330R, Monarch 800, Monarch 880, Monarch
900, Monarch 1000, Monarch 1300, Monarch 1400 (all by Cabot); Color Black FW1, Color
Black FW2, Color Black FW200, Color Black 18, Color Black S160, Color Black S170,
Special Black 4, Special Black 4A, Special Black 6, Printex 35, Printex U, Printex
140U, Printex V, Printex 140V (all by Dexxa); No. 25, No. 33, No. 40, No. 47, No.
52, No. 900, No. 2300, MCF-88, MA600, MA7, MA8, MA100 (all by Mitsubishi Chemical)
and the like.
[0047] Cyan pigments are, not limited to, C.I. Pigment Blue-1, C.I. Pigment Blue-2, C.I.
Pigment Blue-3, C.I. Pigment Blue-15, C.I. Pigment Blue-15:2, C.I. Pigment Blue-15:3,
C.I. Pigment Blue-15:4, C.I. Pigment Blue-16, C.I. Pigment Blue-22, C.I. Pigment Blue-60
and the like.
[0048] Magenta pigments are, not limited to, C.I. Pigment Red-5, C.I. Pigment Red-7, C.I.
Pigment Red-12, C.I. Pigment Red-48, C.I. Pigment Red-48:1, C.I. Pigment Red-57, C.I.
Pigment Red-112, C.I. Pigment Red-122, C.I. Pigment Red-123, C.I. Pigment Red-146,
C.I. Pigment Red-168, C.I. Pigment Red-184, C.I. Pigment Red-202, C.I. Pigment Red-207
and the like.
[0049] Yellow pigments are, not limited to, C.I. Pigment Yellow-12, C.I. Pigment Yellow-13,
C.I. Pigment Yellow-14, C.I. Pigment Yellow-16, C.I. Pigment Yellow-17, C.I. Pigment
Yellow-74, C.I. Pigment Yellow-83, C.I. Pigment Yellow-93, C.I. Pigment Yellow-95,
C.I. Pigment Yellow-97, C.I. Pigment Yellow-98, C.I. Pigment Yellow-114, C.I. Pigment
Yellow-128, C.I. Pigment Yellow-129, C.I. Pigment Yellow-151, C.I. Pigment Yellow-154
and the like.
[0050] In the composition of the present invention, self-dispersible pigments in water are
also usable. As the water-dispersible pigments, there are pigments that adsorb a polymer
on their surface and thus use its steric hindrance, and that use electrostatic repulsion
force. Commercial products of the pigments are CAB-0-JET200, CAB-0-JET300 (both by
Cabot), and Microjet Black CW-1 (by Orient Chemical) and the like.
[0051] Preferably, An amount of the pigment used in the ink of the present invention is
from 0.1 to 50 % by weight based on the weight of the ink. If the pigment content
is less than 0.1% by weight , sufficient image density could not be obtained, and
if it is greater than 50 % by weight, image fixation property may be increased. More
preferable range of the pigment content is 0.5 % by weight to 30 % by weight.
[0052] A known dye may be used in the ink of the present invention, including, for example,
water-soluble dyes such as direct dyes, acid dyes, basic dyes, reactive dyes, water-soluble
dyes for a food color, and insoluble colorant of disperse dyes. These are mentioned
below.
[0053] For example, water-soluble dyes are:
direct dyes such as C.I. Direct Black, -17, -19, -22, -32, -38, -51, -62, -71, -108,
-146, -154;
C.I. Direct Yellow, -12, -24, -26, -44, -86, - 87, -98, -100, -130, -142;
C.I. Direct Red, -1, -4, -13, -17, -23, -28, - 31, -62, -79, -81, -83, -89, -227,
-240, -242, -243;
C.I. Direct Blue, -6, -22, -25, -71, -78, -86, -90, -106, -199;
C.I. Direct Orange, -34, -39, -44, -46, -60;
C.I. Direct Violet, -47, -48;
C.I. Direct Brown, -109;
C.I. Direct Green, -59; and the like;
acid dyes such as C.I. Acid Black, -2, -7, -24, -26, -31, -52, -63, -112, -118, -168,
-172, -208;
C.I. Acid Yellow, -11, -17, -23, -25, -29, -42, -49, -61, -71;
C.I. Acid Red, -1, -6, -8, -32, -37, -51, -52, -80, -85, -87, -92, -94, -115, -180,
-254, -256, -289, -315, -317;
C.I. Acid blue, -9, -22, -40, -59, -93, -102, -104, -113, -117, -120, -167, -229,
-234, -254;
C.I. Acid Orange, -7, -19;
C.I. Acid Violet, -49; and the like;
reactive dyes such as C.I. Reactive Black, -1, -5, -8, -13, -14, -23, -31, -34, -39;
C.I. Reactive Yellow, -2, -3, -13, -15, -17, - 18, -23, -24, -37, -42, -57, -58, -64,
-75, -76, -77, -79, -81, -84, -85, -87, -88, -91, -92, -93, -95, -102, -111, -115,
-116, -130, -131, -132, -133, -135, -137, -139, -140, -142, -143, -144, -145, -146,
-147, -148, -151, -162, -163;
C.I. Reactive Red, -3, -13, -16, -21, -22, -23, -24, -29, -31, -33, -35, -45, -49,
-55, -63, -85, -106, -109, -111, -112, -113, -114, -118, -126, -128, -130, -131, -141,
-151, -170, -171, -174, -176, -177, -183, -184, -186, -187, -188, -190, -193, -194,
-195, -196, -200, -201, -202, -204, -206, -218, -221;
C.I. Reactive Blue, -2, -3, -5, -8, -10, -13, -14, -15, -18, -19, -21, -25, -27, -28,
-38, -39, -40, -41, -49, -52, -63, -71, -72, -74, -75, -77, -78, -79, -89, -100, -101,
-104, -105, -119, -122, -147, -158, -160, -162, -166, -169, -170, -171, -172, -173,
-174, -176, -179, -184, -190, -191, -194, -195, -198, -204, -211, -216, -217;
C.I. Reactive Orange, -5, -7, -11, -12, -13, - 15, -16, -35, -45, -56, -62, -70, -72,
-74, -82, -84, -87, -91, -92, -93, -95, -97, -99;
C.I. Reactive Violet, -1, -4, -5, -6, -22, -24, -33, -36, -38;
C.I. Reactive Green, -5,-8, -12, -15, -19, -23;
C.I. Reactive Brown, -2, -7, -8, -9,-11, -16, -17,
-18, -21, -24, -26, -31, -32, -33; and the like; as well as,
C.I. Basic Black, -2;
C.I. Basic Red, -1, -2, -9, -12, -13, -14, -27;
C.I. Basic Blue, -1, -3, -5, -7, -9, -24, -25, -26, -28, -29;
C.I. Basic Violet, -7, -14, -27;
C.I. Food Black, -1, -2; and the like.
[0054] The coloring materials mentioned above are especially favorable for the ink of the
present invention, but the coloring materials to be used in the ink of the present
invention are not limited to those mentioned above. Preferably, an amount of the dye
used in the ink of the present invention is from 0.1 to 50 % by weight based on the
weight of the ink.
[Additives]
[0055] The composition of the present invention may optionally contain various additives
and auxiliaries.
[0056] One example of additives for the composition is a dispersion stabilizer that allows
a pigment to be stably dispersed in solvent. The composition of the present invention
has the function of dispersing a particulate solid such as pigment in terms of a polymer
having polyvinyl ether structure, but if dispersion of the particulate solid is insufficient,
other dispersion stabilizer may be added. As other dispersion stabilizer, a resin
or a surfactant that has both hydrophilic segments and hydrophobic segments may be
used. The resin having both hydrophilic segments and hydrophobic segments includes,
for example, a copolymer of a hydrophilic monomer and a hydrophobic monomer. The hydrophilic
monomer includes, for example, acrylic acid, methacrylic acid, maleic acid, fumaric
acid, and monoesters of such carboxylic acids, vinylsulfonic acid, styrenesulfonic
acid, vinyl alcohol, acrylamide, methacryloxyethyl phosphate or the like; and the
hydrophobic monomer includes, for example, styrene, styrene derivatives such as α-methylstyrene,
vinylcyclohexane, vinylnaphthalene derivatives, acrylates, and methacrylates or the
like. A various type of copolymer may be used such as random, block or graft copolymers.
Of cause, both the hydrophilic monomers and the hydrophobic monomers are not limited
to those mentioned above. The surfactant may be used such as anionic, nonionic, cationic
or ampholytic surfactants. The anionic surfactant includes, for example, salts of
fatty acids, salts of alkylsulfates, alkylarylsulfonates, alkyl-diarylether disulfonates,
dialkylsulfosuccinates, alkylphosphates, naphthalenesulfonic acid-formalin condensates,
salts of polyoxyethylene-alkylphosphates, and glycerol borate fatty acid esters. The
nonionic surfactant includes, for example, polyoxyethylene alkyl ethers, polyoxyethylene-oxypropylene
block copolymers, sorbitan fatty acid esters, glycerin fatty acid esters, polyoxyethylene
fatty acid esters, polyoxyethylene alkylamines, fluorine-containing surfactants, and
silicon-containing surfactants. The cationic surfactant includes, for example, alkylamine
salts, quaternary ammonium salts, alkylpyridinium salts, and alkylimidazolium salts.
The ampholytic surfactant includes, for example, alkylbetaines, alkylamine oxides,
and phosphatidyl choline. The surfactant is not also limited to those mentioned above.
[0057] Further, an aqueous solvent may optionally added to the composition of the present
invention. Especially for ink-jet ink, the aqueous solvent is effective for preventing
the ink from drying and solidifying around nozzles. One or more different types of
aqueous solvents may be used alone or as mixture. The aqueous solvent may be the same
as those described above. For ink, a content of the aqueous solvent ranges preferably
0.1 to 60 % by weight, more preferably 1 to 25 % by weight based on the total amount
of ink.
[0058] For example, in case of using as ink, the other additives include a pH controlling
agent that ensures the stabilization of ink and the stability of ink with the ink
pipes in recording apparatus; a penetrant having the ability to enhance ink penetration
into recording media and to accelerate the apparent ink drying on them; an antifungal
agent to prevent the development of fungi in ink; a chelating agent that sequesters
metal ions in ink to thereby prevent deposition of metal around nozzles and prevent
deposition of insoluble solids in ink; a defoaming agent that prevents ink from foaming
of a recording liquid during circulation, moving or at the time of production of the
recording liquid; and also antioxidant, antifungal agent, viscosity controlling agent,
electrical conductive agent, UV absorbent, water-soluble dye, disperse dye, oil-soluble
dye, or the like.
[0059] The content (%) of the block polymer used in the present invention is preferably
in the range of 0.1 wt.% to 30 wt.%, more preferably in the range of 0.5 wt.% to 15
wt.%, in the composition. At a concentration in excess of 30 wt.%, viscosity may be
too high particularly for use in ink. At a concentration less than 0.1 wt.%, dispersion
performance or stimuli-responsive performance may be insufficient.
[0060] Ink-jet ink (aqueous dispersion ink) of a preferred embodiment of the ink of the
present invention is described in detail below.
[Method for producing ink-jet ink]
[0061] The preparation method of the ink-jet ink of the present invention, for example,
comprises adding pigment, block polymer and optionally dispersion stabilizer to water
or water-soluble solvent, dispersing them by the use of a dispersing machine, removing
coarse particles by centrifugation etc., then adding water or solvent and additives
thereto, stirring and mixing them, and filtering the resulting mixture.
[0062] The dispersing machine includes, for example, ultrasonic homogenizers, laboratory
homogenizers, colloid mills, jet mills and ball mills, and one or more of these may
be used alone or combination thereof.
[0063] In case where a self-dispersible pigment is used, ink compositions of the present
invention may also be prepared in the same manner as mentioned above.
[0064] Next, the second to sixth aspects of the present invention will be described.
[0065] The second aspect of the present invention is an image-forming method using the composition
of the present invention. The third aspect of the present invention is an image-forming
apparatus relying on the image-forming method. The fourth aspect of the present invention
is a recording medium for use in the image-forming method of the present invention,
especially, a recording medium bearing, beforehand, stimulus characteristics to which
the composition of the present invention responds. The fifth aspect of the present
invention is a composition making a reversible change in response to stimuli among
the compositions of the present invention, and a device using the composition. The
sixth aspect of the present invention is a novel ABC type triblock polymer compound.
[0066] These aspects of the present invention will be described below.
[Image-forming method and image-forming apparatus]
[0067] The ink composition of the present invention can be used for various image-forming
apparatuses employing various methods, such as printing methods, ink-jet process,
and electrophotography, and can be drawn as an image by an image-forming method using
any of the apparatuses.
[0068] The image-forming method of the present invention is a method for performing excellent
image formation with the use of the stimuli-responsive composition of the present
invention. According to this method, recording is made by giving stimuli to the composition
of the present invention at any point in time during the image-forming process and
causing a change of the micelle state by the given stimuli. In the present invention,
no restrictions are imposed on the type and number of changes of the state, and on
the type and number of the stimuli given. For example, the image formation of the
present invention may be completed when one of the blocks of the block polymer has
changed from hydrophobic to hydrophilic in response to stimuli causing a change in
temperature. Alternatively, the image formation may be completed such that one of
the blocks of the block polymer changes from hydrophobic to hydrophilic in response
to stimuli causing a change in temperature, and then the pH is changed, whereby the
micelle radius is greatly increased, with the hydrophilic property of the block being
maintained, and the viscosity is increased accordingly.
[0069] The image-forming method of the present invention is preferably an image-forming
method which comprises ejecting the ink composition of the present invention from
an ink ejection portion to impart the ink composition onto a recording medium, thereby
making a recording. In the present invention, a substance or composition giving the
stimuli may be provided beforehand on a recording medium. Preferably used for image
formation is a method according to the ink-jet process, by which thermal energy is
applied to ink to eject the ink.
[0070] For use as ink for ink-jet recording, the composition of the present invention can
be used, for example, in the following modes:
(a) For use as ink responsive to temperature stimuli:
Because of temperature stimuli ascribed to the difference between the temperature
of ink within the ink tank and the temperature of ink on the recording medium having
the ink adhered thereto by ejection, the ink for ink-jet recording of the present
invention undergoes a change, suddenly increasing in viscosity.
(b) For use as ink responsive to stimuli due to pH change:
The pH of the ink within the ink tank changes under the influence of a recording medium
after the ink adheres to the recording medium. Because of this pH change, the ink
for ink-jet recording of the present invention undergoes a change, increasing in viscosity.
(c) For use as ink responsive to stimuli due to concentration change:
Because of a change in the concentration of ink ascribed to the difference between
the concentration of ink within the ink tank and the concentration of the ink after
evaporation of water and an aqueous solvent contained in the ejected ink, or after
absorption of water and an aqueous solvent contained in the ejected ink by a recording
medium, the ink for ink-jet recording of the present invention undergoes a phase change,
increasing in viscosity.
[0071] The change of the ink properties can improve color blurring and feathering and provide
excellent ink fixation. The changes of ink properties are not limited to the examples
as mentioned above.
[0072] Various methods can be employed for applying stimuli to the ink. One preferred method
comprises mixing a stimuli-giving composition with the stimuli-responsive ink or contacting
it with the ink. For the pH-responsive ink of above (b) for example, an ink-jet process
may be applied as a method for mixing the ink with a composition having a desired
pH. As disclosed in JP-A 63185/1989, a stimuli-giving composition may be ejected through
an ink-jet head onto the entire area of forming an image; or as disclosed in JP-A
216392/1996, the amount of the stimuli-giving composition may be controlled to ensure
better image formation. The stimuli-giving composition may be used as an ink composition
containing dye or pigment. For example, any ink of cyan-magenta-yellow-black (CMYK)
inks used in a color ink-jet process may be a stimuli-giving ink, and any other ink
of CMYK inks may be a stimuli-responsive ink to improve the color blurring. Regarding
the matter as to which of CMYK is a stimuli-responsive ink and which of other CMYK
is a stimuli-giving ink, there are various combinations of inks. In the present invention,
any combination of inks is employable with no limitation on the selection. A stimuli-giving
composition and a stimuli-responsive ink are not limited to those described above.
[0073] It is also preferred to apply, beforehand, a contrivance for giving stimuli to the
recording medium. For example, a method can be named in which acid paper is recorded
with the use of an acid-responsive ink among pH-responsive inks. In this case, the
recording medium has the function of giving stimuli to the stimuli-responsive ink
of the present invention. Such a recording medium is included in the present invention.
That is, the present invention relates to a recording medium having the function of
giving such stimuli. In the present invention, the recording medium may be in any
known form. For example, plain paper, thermal recording paper, or acid paper can be
named.
[0074] As ink-jet printers using the ink for ink-jet recording of the present invention,
various ink-jet recorders are available, such as a piezo ink-jet system using a piezoelectric
element, and a thermal ink-jet system which applies thermal energy to cause bubbling,
thereby making recording.
[0075] Next described is the outline of an ink-jet recording apparatus with reference to
Fig. 1. Fig. 1 shows one example of the constitution of an ink-jet recording apparatus,
and is not intended to restrict the scope of the present invention.
[0076] Fig. 1 is a block diagram showing an ink-jet recording apparatus.
[0077] Fig. 1 is to illustrate a case of recording an image on a recording medium by moving
the head in the apparatus. In Fig. 1, an X-direction driving motor 56 and a Y-direction
driving motor 58, by which the head 70 is driven in X-Y direction, are connected to
CPU 50 which controls the entire movement of the apparatus, via an X-motor driving
circuit 52 and a Y-motor driving circuit 54, respectively. According to the indication
of CPU, the X-direction driving motor 56 and the Y-direction driving motor 58 are
driven via the X-motor driving circuit 52 and the Y-motor driving circuit 54, respectively,
and the position of the head 70 relative to a recording medium is thereby determined.
[0078] As shown in Fig. 1, a head driving circuit 60 is connected to the head 70, in addition
to the X-direction driving motor 56 and the Y-direction driving motor 58, and CPU
50 controls the head driving circuit 60, by which the head 70 is driven, that is,
the ejection of ink-jet ink and the like is done. In addition, an X-encoder 62 and
a Y-encoder 64 that detect the head position are connected to CPU 50, and the position
information of the head 70 is inputted into CPU 50. A control program is also inputted
into the program memory 66. Based on the position information from the control program,
the X-encoder 62 and the Y-encoder 64, the head 70 is moved to be located in a desired
position on a recording medium, and ejects ink-jet ink. In that manner, a desired
image is recorded on the recording medium. In case where plural ink-jet inks are loaded
in the image-recording apparatus, the above-mentioned operation is repeated for every
ink-jet ink for a total of predetermined times to thereby record a desired image on
a recording medium.
[0079] After the ink-jet ink has been ejected, if desired, the head 70 may be moved to a
position of a cleaning means (not shown) which is to remove the excess ink from the
head 70, whereby the head 70 can be cleaned by wiping it. For cleaning the head, any
conventional method may be used.
[0080] After an image recording is completed, the recorded medium is transferred by a transfer
mechanism (not shown), and a new recording medium is set in the apparatus.
[0081] Within the scope and the sprit of the present invention, the embodiment of the present
invention illustrated hereinabove may be modified or changed. For example, although
the above illustrated embodiment mentioned, in which the head 70 is moved in X-Y direction
is described, the image recording is performed by moving the head in X-direction (or
Y-direction) only and the recording medium in Y-direction (or X-direction) with linking
them each other.
[0082] In the present invention, the head provide an superior result, which has a thermal
energy-generating means (e.g., electro-thermal transducer, laser) for generating the
thermal energy as the energy source for ejecting the ink-jet ink, and which eject
the ink-jet ink by the thermal energy. Specifically, in the system, fine and precision
images can be formed. Superior image recording is achieved by using of the ink-jet
ink of the present invention.
[0083] Regarding the configuration and the principle of a typical apparatus equipped with
the thermal energy-generating means, the basic principles disclosed, for example,
in USP 4,723,129 and 4,740,796 are preferably used in carrying out the present invention.
The system disclosed may apply to both on-demand type and continuous type, but especially
it is effective to on-demand type. This is because in on-demand type, at least one
driving signal, which gives rapid temperature increase that corresponds to eject information
and exceeds nucleate boiling, is applied to an electro-thermal transducer that hold
a liquid and is located in accordance with path, thereby to allow thermal energy to
be generated and to cause film boiling on a heated surface of the head, and, as a
result, foams corresponding to the driving signal in one-to-one are formed in liquid.
With the growth and the contraction of the foam, the liquid is ejected from openings
for ejecting, and at least one droplet is formed. If the driving signal is pulse-shape,
it is more preferable since the foam growth and contraction may be attained suitably
and immediately, the ejection of the liquid having superior responsiveness is achieved.
For the pulse-shaped driving signal, preferred are those described in USP 4,463,359
and 4,345,262. When the condition described in USP 4,313,124, which is an invention
relating to the rate of increase of the temperature of the heated surface, is adopted,
more effective ejection is achieved.
[0084] Regarding the head configuration, a configuration described in USP 4,558,333 and
4,459,600 that disclose a configuration in which the heated surface is located at
a bending portion, may be used in addition to a configuration of a combination the
ejecting opening, the flow path of liquid and electro-thermal transducer as in the
above-mentioned patent specifications, and is also within the scope of the present
invention. In addition, the present invention has also effective results, when the
invention is adopted other constitution that are based on JP-A 123670/1984 that discloses
the configuration in which, for plural electro-thermal transducers, a common slit
is used as an ejecting portion of the electro-thermal transducer, or on JP-A 138461/1984
that discloses the configuration in which an opening able to absorbed the pressure
waves of thermal energy corresponds to an ejecting portion. In other words, even if
any type of the head is used, according to the present invention an ink-jet ink is
ejected reliably and efficiently.
[0085] Further, the present invention is also conveniently applied to the head of a full-line
type having the length corresponding to the maximum width of recording media in the
image-forming apparatus of the present invention. The head of this type may have a
configuration in which plural head units are combined to satisfy the intended length
of the head, or the head may be integrated as one head.
[0086] Still further, the present invention is also effective in serial-type apparatus where
the head is fixed to the body of the image-forming apparatus, or where the head is
an exchangeable chip-type one which may be, when mounted on the body of the image-forming
apparatus, electrically connected to the body and supplied ink from the body.
[0087] The apparatus of the present invention may be provided with a means for removing
a liquid drop. Provided with it, much better ejecting effect is achieved.
[0088] Addition of any preliminarily auxiliary means into the apparatus of the present invention
is preferable since they further stabilize the effect of the present invention. Specifically,
the additional preliminary means includes a capping means for head; a pressure or
suction means; an electro-thermal transducer or other heating elements, or a means
for pre-heating comprising a combination thereof; and a pre-ejecting means for ejection
different from a means for ejecting ink.
[0089] The most effective apparatus for the present invention is one which is able to realize
the above-mentioned film boiling manner.
[0090] In the apparatus of the present invention, the amount of ink ejected through ejection
ports of an ejection head for ink-jet recording ink is preferably in the range of
0.1 picoliter to 100 picoliters.
[0091] Also, the aqueous dispersion ink of the present invention can be used in an indirect
recorder using a recording system by which ink is printed on an intermediate transfer
member, and then transferred onto a recording medium such as paper. The aqueous dispersion
ink may be applied to an apparatus utilizing an intermediate transfer member according
to a direct recording system.
[0092] The composition of the present invention can also be used as an element or device.
The composition which makes a reversible change can be used as an element or device.
For example, the use of a composition containing the aforementioned block polymer
responsive to a temperature change makes it possible to prepare an optical device
in which the state of light scattering changes according to a change in the size of
a micelle. This optical device can be formed by encapsulating the composition of the
present invention into a cell transparent to visible light.
[0093] Next, the sixth aspect of the present invention will be described.
[0094] The sixth aspect of the present invention relates to a novel ABC type block polymer,
, in which the respective blocks of the ABC type block polymer change in nature from
hydrophobic to hydrophilic or from hydrophilic to hydrophobic in response to stimuli,
and this change occurs sequentially, first in the A block, then in the B block, and
finally in the C block.
[0095] The ABC type triblock polymer compound of the present invention is preferably an
ABC type triblock polymer compound containing a polyvinyl ether structure. Concretely,
it is an ABC type triblock polymer compound having a repeating unit of the polyvinyl
ether structure of the following general formula (1) described in connection with
the first aspect of the invention:
General formula (1)
-(CH
2-CH(OR
1))- (1)
[0096] In the general formula (1), the definitions for R
1 in the present invention are as follows:
(I) R1 is selected from linear, branched or cyclic alkyl groups having 1 to 18 carbon atoms,
phenyl (Ph), pyridyl (Pyr), Ph-Ph, Ph-Pyr, or -(CH(R2)-CH(R3)-O)1-R4 or -(CH2)m-(O)n-R4; the hydrogen on the aromatic ring can be substituted by a linear or branched alkyl
group having 1 to 4 carbon atoms, and the carbon in the aromatic ring can be substituted
by nitrogen; 1 is selected from integers of 1 to 18, m is selected from integers of
1 to 36, n is 0 or 1; R2 and R3 are each independently H or CH3, and preferably, both R2 and R3 are H (that is, -(CH2-CH2-O)1-R4); R4 comprises H, a linear, branched or cyclic alkyl group having 1 to 18 carbon atoms,
Ph, Pyr, Ph-Ph, Ph-Pyr, - CHO, -CH2CHO, -CO-CH=CH2, -CO-C(CH3)=CH2, or CH2COOR5, provided that when R4 is other than hydrogen, the hydrogen on the carbon atom can be substituted by a linear
or branched alkyl group having 1 to 4 carbon atoms, F, Cl or Br, and the carbon in
the aromatic ring can be substituted by nitrogen; and R5 is H or an alkyl group having 1 to 5 carbon atoms.
[0097] Preferred definitions of R
1 are as follows:
(II) R1 is selected from linear, branched or cyclic alkyl groups having 1 to 18 carbon atoms,
or - (CH(R2)-CH(R3)-O)1-R4 or -(CH2)m-(O)n-R4; 1 and m are each independently selected from integers of 1 to 6; n is 0 or 1; R2 and R3 are each independently H or CH3; R4 comprises H, a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms,
Ph, Pyr, Ph-Ph, or CH2COOR5, provided that when R4 is other than hydrogen, the hydrogen on the carbon atom can be substituted by a linear
or branched alkyl group having 1 to 4 carbon atoms, F, C1 or Br, and the carbon in
the aromatic ring can be substituted by nitrogen; and R5 is H or an alkyl group having 1 to 5 carbon atoms.
(III) R1 is selected from linear, branched or cyclic alkyl groups having 1 to 18 carbon atoms,
or - (CH2-CH2-O)1-R2 or -(CH2)m-(O)n-R2; 1 and m are each independently selected from integers of 1 to 6; n is 0 or 1; R2 comprises H, a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms,
Ph, Pyr, Ph-Ph, or CH2COOR3, provided that the carbon in the aromatic ring can be substituted by nitrogen; and
R3 is H or an alkyl group having 1 to 5 carbon atoms.
(IV) R1 is selected from -(CH2-CH2-O)1-R2 or - (CH2)m-(O)n-R2; 1 and m are each independently selected from integers of 1 to 6; n is 0 or 1; and
R2 is H or a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms.
(V) R1 is selected from -(CH2-CH2-O)1-R2; 1 is selected from integers of 1 to 2; and R2 is H or a linear, branched or cyclic alkyl group having 1 to 4 carbon atoms.
(VI) R1 is selected from -(CH2-CH2-O)1-R2; 1 is selected from integers of 1 to 2; and R2 is H, CH3 or C2H5.
[0098] The ABC type triblock polymer of the present invention, whose polyvinyl ether structure
has the repeating unit of the general formula (1), preferably has a total of 20 or
more, but 40,000 or less, of the repeating units.
[0099] Particularly in the present invention, of the above-described ABC type block polymers
of the present invention, a novel ABC type triblock polymer compound is characterized
in that the change from hydrophobic property to hydrophilic property or the change
from hydrophilic property to hydrophobic property in the respective blocks, caused
in response to stimuli, occurs sequentially, first in the A block, then in the B block,
and finally in the C block.
[0100] A further ABC type triblock polymer compound of the present invention is a compound
having the following general formula (2).
General formula (2)
-[CH
2-CH(O-CH
2-CH
2-OCH
3)]
x-b-{[CH
2-CH(O-CH
2-CH
2-OC
2H
5)]
p-r-[CH
2-CH(O-CH
2-CH
2-OCH
3)]
q}
y-b-[CH
2-CH(O-CH
2-CH
2-OC
2H
5)]
z-
where x + y + z is 20 or more, but 40,000 or less, p and q are independently 0.01
or more, but 0.99 or less, p + q is 1, b represents a block structure, and r represents
a random structure.
Examples
[0101] The present invention will be described in detail by Examples, but is not limited
thereto.
Example 1:
<Synthesis of polymer>
Preparation of monomers:
[0102] 2-Methoxyethyl vinyl ether (hereinafter referred to as MOVE) and 2-ethoxyethyl vinyl
ether (hereinafter referred to as EOVE) were synthesized by refluxing 2-chloroethyl
vinyl ether and sodium methoxide and sodium ethoxide, respectively, with the use of
a tetrabutylammonium iodide catalyst (H.J. Schneider, U.S. Pat. 3,062,892(1962)).
Synthesis of ABC block polymer (II-g, x = y = z = 160, p = q = 0.5:
[0103] The interior of a glass container fitted with a three-way stopcock was purged with
nitrogen, and then heated at 250°C under a nitrogen gas atmosphere to remove adsorption
water. After the temperature of the system was returned to room temperature, 16 mmols
of EOVE, 25 mmols of ethyl acetate, 0.1 mmol of 1-isobutoxyethyl acetate, and 11 ml
of toluene were added. When the temperature inside the system reached 0°C, 0.5 mmol
of ethylaluminum sesquichloride was added to initiate polymerization, thereby synthesizing
an A component of an ABC block polymer. The molecular weight was monitored by Gel
permeation chromatography (GPC) in a time-shared manner. After polymerization of the
A component was completed, polymerization of a B component was carried out with the
simultaneous addition of 8 mmols each of the B component EOVE and MOVE. Then, the
molecular weight was monitored by GPC in a time-shared manner. After polymerization
of the B component was completed, 16 mmols of a C component, MOVE, was added to polymerize
the C component. Termination of the polymerization reaction was performed by adding
0.3 wt.% of an ammonia/methanol solution into the system. Dichloromethane was added
to the solution of the mixture after completion of the reaction to dilute it. The
diluted mixture was washed three times with a 0.6N hydrochloric acid solution, and
then three times with distilled water, concentrated to dryness by an evaporator to
give a residue. The residue was dried in vacuo to give a triblock polymer, the desired
product. The compound was identified by NMR and GPC (Mn = 4.8×10
4, Mn/Mw = 1.4 (calculated as polystyrene)).
[0104] If the B component and the C component are not added during the synthesis of the
polymer, the following homopolymer composed of EOVE can be synthesized:
-[CH
2-CH(OCH
2CH
2O-C
2H
5)]
160-
[0105] Unless the C component is added, the following diblock polymer comprising EOVE and
a copolymer of EOVE and MOVE can be synthesized:
-[CH
2-CH(OCH
2CH
2-OCH
3)]
160-b-{[CH
2-CH(OCH
2CH
2-OC
2H
5)]
0.5-r-[CH
2-CH(OCH
2CH
2-OCH
3)]
0.5}
160-
[0106] If the conversion of the monomer to the polymer is terminated halfway, the polymer
with a different chain length can be obtained. At the time of the synthesis described
above, not only a triblock polymer (II-g, x = y = z = 120, p = q = 0.5), but also
the compounds described in the following formulae (i) to (iii) were synthesized:
Formula (i)
-[CH
2-CH(OCH
2CH
2O-C
2H
5)]
x-
(x = 10, 60 or 120)
Formula (ii)
-[CH
2-CH(OCH
2CH
2-OCH
3)]
x-b-{[CH
2-CH(OCH
2CH
2-OC
2H
5)]
0.5-r-[CH
2-CH(OCH
2CH
2-OCH
3)]
0.5}
y-
(x = 160, y = 60, 80 or 120)
Formula (iii)
-[CH
2-CH(OCH
2CH
2-OCH
3)]
x-b-{[CH
2-CH(OCH
2CH
2-OC
2H
5)]
0.5-r-[CH
2-CH(OCH
2CH
2-OCH
3)]
0.5}
y-b-[CH
2-CH(OCH
2CH
2-OC
2H
5)]
z-
(x = 160, y = 160, z = 20, 80, 120)
[0107] Furthermore, polymers having various degrees of polymerization can be synthesized
by increasing or decreasing the amount of the monomer added. Besides, various polymers
(II- h, i, j, k, and l) can be synthesized in the same manner by employing the above-described
method and changing the monomer structure.
<Preparation of pigment dispersion ink>
[0108] 3 Parts by weight of a pigment (MOGUL-L, Cabbot), 5 parts by weight of the above-mentioned
block polymer, and 3 parts by weight of diethylene glycol were added to 89 parts by
weight of ion-exchanged water. The mixture was heated to 50°C, and dispersed using
an ultrasonic homogenizer. The dispersion was filtered under pressure through a 1
µm filter to prepare a stimuli-responsive ink.
<Bulk characteristics of ink>
[0109] The DSC of the above ink was measured, and peaks of phase transition of the block
polymer were observed at 18°C, 38°C and 67°C. These peaks were suggested to correspond,
respectively, to a phase transition in which the EOVE block changes from hydrophilic
to hydrophobic, a phase transition in which the MOVE-EOVE random polymerization block
changes from hydrophilic to hydrophobic, and a phase transition in which the MOVE
block changes from hydrophilic to hydrophobic.
[0110] The same composition prepared with the exclusion of the pigment was observed at different
temperatures. At temperatures in excess of 67°C, a suspension of the insolubilized
polymer was observed. At temperatures between 38°C and 67°C, the polymer dispersed
as a micelle in the liquid and appeared transparent. At temperatures between 38°C
and 18°C, a marked increase in viscosity probably due to an increase in micelle interaction
was observed. The composition with a block polymer concentration of 18 wt.% was prepared,
and the above temperature process was repeated. At temperatures between 38°C and 18°C,
an even more marked increase in viscosity occurred, resulting in gel.
[0111] Particle size measurements were made using a dynamic light scattering measuring device
(Otsuka Denshi). At 60°C, the micelle particle size, as the average particle size
(diameter), was 50 nm. At 50°C, the micelle particle size, as the average particle
size (diameter), was 61 nm. This particle size changed to 153 nm at 27°C.
Comparative Example 1:
[0112] An ink composition was prepared by mixing 15 wt.% of a self-dispersible pigment (CAB-0-JET300,
Cabbot), 0.5 wt.% of a surface active agent (NONION E-230, NOF CORP.), 10 wt.% of
ethylene glycol, and 74.5 wt.% of ion-exchanged water.
Example 2:
<Printing test>
[0113] The ink-jet inks for an ink-jet process, prepared in Example 1 and Comparative Example
1, were evaluated for fixing strength. The ink-jet inks of Example 1 and Comparative
Example 1 were each charged into a recording head of a bubble jet (registered trademark)
printer (trade name: BJF800) of CANON INC., and recorded onto a sheet of plain paper
with the use of the ink-jet printer.
[0114] Evaluations were made by pressing another blank sheet of plain paper, 30 seconds
after recording, against the printed area under a load of 4.9×104 N/m
2, and observing whether or not the ink adhered to the blank sheet of plain paper.
[0115] The above printer was installed in a space kept at 42°C, and the ink composition
of Example 1 set at 55°C was introduced into the ink tank. Immediately thereafter,
the ink composition was recorded onto a sheet of plain paper, and the recorded sheet
was immediately withdrawn at room temperature. Thirty seconds after recording, another
blank sheet of plain paper was pressed against the printed area under a load of 4.9×104
N/m
2, and it was observed whether or not the ink adhered to the blank sheet of plain paper.
No adhesion was observed. The same experiments were conducted using the ink of Comparative
Example 1, and adhesion of a black color was observed.
Example 3:
[0116] A sheet of plain paper, a recording medium, was sprayed with a 5 wt.% aqueous solution
of polyacrylic acid (pH 4) to prepare a recording medium capable of giving stimuli.
Ink-jet recording was performed on this recording medium in the same manner as in
Example 2. Satisfactory fixing properties similar to those in Example 2 were achieved.
The block polymer of Example 1 is known to form a complex with a carboxylic acid.
Thus, it is speculated that the interaction of this polymer with the recording medium,
in addition to the temperature-associated property change of Example 2, contributed
to achieve the satisfactory fixing properties.
Example 4:
[0117] Two panes of transparent glass were provided, and an aqueous dispersion composition
of 15 wt.% of the block polymer synthesized in Example 1 and 3 wt.% of MOGUL-L (Cabbot)
(water dispersion compsition) was placed on one of the panes. A structural adhesive
was applied so as to surround the region where the composition was placed. The other
pane of transparent glass was contacted under pressure with the former pane to encapsulate
the sample composition. The resulting cell was subjected to a cycle of a temperature
rise and a temperature fall between 50°C and 80°C. At a temperature exceeding 67°C,
an opaque state involving a suspension of the insolubilized polymer was observed.
At a temperature between 38°C and 67°C, a state in which the insolubilized polymer
dispersed as a micelle in the liquid to become transparent was observed. Hence, an
optical element or device capable of controlling transmittance in response to a temperature
change can be realized.
[0118] The present invention has been described in detail with respect to preferred embodiments,
and it will now be apparent from the foregoing to those skilled in the art that changes
and modifications may be made without departing from the invention in its broader
aspects, and it is the intention, therefore, in the appended claims to cover all such
changes and modifications as fall within the true spirit of the invention.